High stereospecific polybutylene polymer and highly active process for preparation thereof

ABSTRACT

Disclosed is a process for the preparation of a high stereospecific (isotactic) polybutylene polymer comprising the step of polymerizing a reactive monomer, 1-butene, which is used or is not used as a solvent, in the presence of catalyst and inert gas. According to the present invention, it is possible to prepare a high stereospecific polybutylene polymer in much higher activity than that of any other known processes for the preparation of a high stereospecific polybutylene polymer. The high stereospecific polybutylene polymer according to the present invention is a homopolymer of 1-butene, or a copolymer containing a-olefin and up to 40% by weight of a comonomer, wherein titanium in the catalyst residues is not detected in the ppm level, stereospecificity (Isotactic Index, mmmm %) determined by  13 C-NMR is 96 or more, molecular weight distribution (Mw/Mn) is 3-6, and molecular weight distribution (Mw/Mn) can be controlled to 8 or more.

TECHNICAL FIELD

The present invention relates to a high stereospecific polybutylenepolymer and a highly active process for preparation thereof, and moreparticularly relates to a high stereospecific polybutylene polymer and ahighly active process for preparation thereof, wherein the process iscarried out using inert gas, which has not been used in the conventionalpolymerization processes of 1-butene, and so titanium in the catalyticresidues is not detected in the ppm level.

BACKGROUND ART

Generally, a stereospecific polybutylene is a semi-crystal polymer of1-butene as a monomer, and is a polyolefin having a high molecularweight, and has generic physical properties similar to those ofpolyethylene or polypropylene.

A stereospecific polybutylene has characteristic features such as highflexural resistance, compatibility with other polymers, rheologicalproperties, crystal behavior and the like. Also, it has a similardensity to that of polypropylene and low density polypropylene, and hasa similar melting point to that of high density polyethylene. Also, astereospecific polybutylene has such an excellent stability that it hasa long-lasting durability even at a high temperature.

Furthermore, a stereospecific polybutylene has the advantage that it canbe readily used in the processes such as extrusion, injection, blowmolding and the like, because it can be readily used in the conventionalmachines for said processes in which polyolefin has been used.

Available temperature range of such a stereospecific polybutylene isapproximately −20˜105° C. and a stereospecific polybutylene can beapplied to various manufactured goods such as hot or cold water pipe,opening of soft package, polypropylene film, fiber-softening agent orcapability-enhancing agent of hot melt adhesives and the like.

A stereospecific polybutylene can be obtained by the process thathydrocarbon is used as a solvent or the process that 1-butene in itselfis used as a solvent Currently, due to the problem of separation afterpreparation and the like, a stereospecific polybutylene has beenobtained by the latter process commercially.

Generally, a stereospecific polybutylene is obtained by polymerizing1-butene in the presence of main catalyst based on organic aluminiumcompound such as diethylaluminium chloride and titanium trichloride.

According to this process, the stereospecificity of producedpolybutylene is not high enough and, therefore, non-stereospecificpolybutylene should be removed. Moreover, due to its low activity, thisprocess needs the step of removing catalytic residues that deterioratephysical properties of the polymer.

A stereospecific polybutylene can be obtained by polymerizing 1-butenein the presence of the catalytic system consisting of internal electrondonor and titanium supported on magnesium chloride.

However, this process does not have a high catalytic activity comparedto that of a highly active conventional process for the preparation ofpolyethylene or polypropylene and, therefore, this process has theproblem that titanium components still resides in the polymer in ppm(weight) level.

EP 187,034 A2 discloses a conventional process for the preparation of astereospecific polybutylene.

In this process, so as to prepare a high stereospecific polybutylene inthe form of particle, a lower hydrocarbon such as normal butane,isobutane, normal pentane, isopentane and cyclopentane as a solvent, aZiegler-Natta catalyst, an organic aluminium compound, an externalelectron donor (Lewis base) and 1-butene are used in the process ofpolymerization at 20˜45° C. This process is intended to solve theproblem of conventional processes that the used solvent should beremoved from produced polybutylene.

This process has advantages that the step of removing non-stereospecificpolybutene-1 is not necessary due to the very high stereospecificity of80 or more of produced polybutylene and the separation of producedpolybutylene from the solvent is easy.

However, since the catalytic activity in this process is low (2,360g/g-cata 4 h, that is, 590 g/g-cata h), the step of removing catalyticresidues that deteriorate physical properties of the polymer isrequired. Also, the catalytic efficiency of this process is too low forthe process to be applied effectively to commercial applications.

U.S. Pat. No. 6,306,996 B1 discloses another conventional process forthe preparation of a stereospecific polybutylene.

In this process, polybutylene is obtained by 2-stage polymerization of1-butene in the presence of main catalyst supported on magnesiumchloride, wherein 1-butene in itself is used as a solvent and a monomer;and tributylaluminium (TIBA) is used, and diisopropyl dimethoxy silane(DIPMS) is used as an external electron donor.

According to this process, we can obtain the polybutylene that hassatisfactory properties, for example, high stereospecificity, a contentof catalytic residues expressed in terms of titanium ppm of 50 or less,a molecular weight distribution (Mw/Mn) of 6 or more. Also, this processshows the catalytic activity based on polybutylene homopolymer of 14,000g/g-cata. 4 h, that is, 3,500 g/g-cata. h.

However, this process also has much lower catalytic activity than thatof a highly active process for the preparation of polyethylene orpolypropylene and, therefore, it has a long reaction time, which meansthe decrease of its productivity.

DISCLOSURE OF THE INVENTION

The present invention is intended to solve the problems as describedabove, and an object of the present invention is to provide a highlyactive process for the preparation of a high stereospecific polybutylenepolymer, wherein the polybutylene polymer has a high stereospecificity,and titanium is not detected in the ppm (weight) level, and it ispossible to polymerize 1-butene with a high activity similar to that ofa highly active process for the preparation of polyethylene orpolypropylene.

Another object of the present invention is to provide a highstereospecific polybutylene polymer prepared by the process of thepresent invention, which has a high stereospecificity and, also, inwhich titanium is not detected in the ppm (weight) level compared to thepolybutylene prepared by the conventional processes.

To achieve above objects, the highly active process for the preparationof the high stereospecific polybutylene polymer of the present inventionis characterized by comprising the step (S1) of polymerizing a reactivemonomer, 1-butene, which is used or is not used as a solvent, in thepresence of catalyst and inert gas.

The step (S1) is characterized by increasing pressure in apolymerization reactor using the inert gas to a higher pressure thangas-liquid equilibrium pressure of reactants at a given reactiontemperature.

The step (S1) is characterized by using the inert gas which is one ormore selected from the group consisting of nitrogen, helium and argon.

The step (S1) is characterized by having a reaction temperature be 10°C.˜110° C.

The step (S1) is characterized by having the reaction temperature be 20°C.˜90° C.

The high stereospecific polybutylene polymer prepared by the process ofthe present invention is characterized by being a homopolymer of1-butene or a copolymer containing α-olefin and up to 40% by weight of acomonomer, and having such properties that 1) titanium in catalyticresidues is not detected in ppm (weight) level, 2) stereospecificity(Isotactic Index, mmmm %) determined by ¹³C-NMR is 96 or more, 3)molecular weight distribution (Mw/Mn) is 3˜6.

The process for the preparation of the high stereospecific polybutylenepolymer according to the present invention is as follows:

Inert gas which has never been used in the conventional processes forthe preparation of a high stereospecific polybutylene polymer is used onthe polymerization of the present invention and so, contrary to thegeneral rections which use inert gas, a high stereospecific polybutylenepolymer can be obtained with a high catalytic yield similar to that of ahighly active process for the preparation of polyethylene orpolypropylene.

With regard to the polymerization process, the following description ismostly focused on the procedure in batch reactor, but it is clear thatthe procedure of the present invention is not limited to using thereactor and the procedure of the present invention can be carried out inall kinds of reactors such as CSTR, tubular reactor or other reactors aswell as batch reactor.

The first step is to introduce 1-butene that is used as a solvent and/ora reaction monomer to a reactor, wherein a pretreatment is carried outwith introduced cocatalyst (g) and external electron donor (h).

Here, after the reactor is purged by vacuumizing and introducing inertgas stream repeatedly, the pretreatment is carried out while 1-butene, acocatalyst (g) and an external electron donor (h) are introduced to thereactor and then mixed.

1-Butene is polymerized while the cocatalyst (g) contacts with maincatalyst (i) such as Ziegler-Natta catalyst and the like in thefollowing second step. Also, the external electron donor (h) isintroduced to maximize the stereospecificity.

In this first step, an anticatalyst, for example moisture, oxygen,carbon monoxide, carbon dioxide, acetylene, etc. in the reactor shouldbe removed before the polymerization. The removal can be carried out bya vacuum purging, an inert gas (j) purging or a combination thereof.

Next, in the second step, polymerization is carried out by introducingmain catalyst (i) and inert gas (j) to the reactor and then elevatingtemperature to the corresponding polymerization temperature withagitation. Here, a molecular weight control agent is addedsimultaneously.

The second step is the step that main catalyst such as Ziegler-Nattacatalyst and the like, which is a polymerization catalyst, is introducedto the reaction system; a molecular weight control agent is added;pressure is applied by using inert gas (j); and then polymerization iscarried out at the corresponding elevated polymerization temperaturewith agitation.

Here, the polymerization temperature is 10° C.˜110° C., preferably 20°C.˜90° C. The pressure of the reactor is approximately 1˜1000 bar,preferably 1˜60 bar.

With regard to the polymerization time, average residence time isapproximately 10 min˜20 hrs, preferably approximately 30 min˜4 hrs forbatch polymerization, and is also approximately 10 min˜20 hrs,preferably approximately 30 min˜4 hrs for polymerization using CSTR.

The high activity of polymerization can be obtained at the reactiontemperature, the reaction pressure and the reaction time as describedabove.

To control the molecular weight of polymer, hydrogen can be used as amolecular weight control agent. Also, the molecular weight of polymercan be controlled by adjusting the reaction temperature.

In this second step, the activity of polymerization is increasedconsiderably by carrying out the polymerization reaction at a higherpressure than gas-liquid equilibrium pressure at a given reactiontemperature with introducing the inert gas (j), which does not take partin any reaction in the reaction system, so as to maintain the constantpressure as described above.

In this step, when suitable gas pressure is not applied, the activity ofpolymerization will be relatively reduced and the activity of catalystwill be relatively reduced in the preparation of polybutylene.

In this step, if necessary, a small amount of α-olefin having from 1 to20 of carbon atom(s) such as ethylene or propylene can be introduced asa comonomer.

Next, in the third step, produced polybutylene is agitated in apolymerization reactor or a separate container, wherein stabilizers andadditives (k) are introduced.

In this step, antioxidants etc. can be added to reduce the degradationof the polybutylene, which is due to the heat that will be applied tothe polybuthylene in the process of transferring the polybutylene afterdepressurization if the polybutylene is used on industrial applications.

With regard to the post-reactor step, in case of low densitypolyethylene (LDPE) of bulk-solution process, which is conceptuallysimilar to the polybutylene, it is general that stabilizers andadditives are introduced to extractor, which is the final step, byadding masterbatch (MB) at the same time. However, when stabilizers andadditives (k) are introduced in the third step of the present inventionas described above, the stabilizers and the additives (k) can be mixedmore homogeneously with polybutylene. Also, if the stabilizers and theadditives (k) can be dissolved in hydrocarbons, or if they have theparticle size in the range of nanometer even though they can not bedissolved in hydrocarbons, they can be mixed in molecular level.

In the third step, when the polymerization reactor is a batch reactor,the stabilizers and the additives (k) can be introduced directly withouta separate reactor, and when the polymerization reactor is a continuousstirred tank reactor (CSTR), homogeneous mixing can be carried out byintroducing the stabilizers and the additives (k) into the apparatusthat is equipped with a separate stirrer or a miscible device.

Next, in the fourth step, after pressure is reduced, unreacted monomersare removed and the polybutylene is made in the form of solid.

In this step, pressure is reduced sufficiently and the polybutylene inthe form of solid is obtained.

Hereinafter, the respective components that are used in the process forthe preparation of the polybutylene according to the present inventionare described in detail.

As the main catalyst (i), a titanium trichloride catalyst, a solvay typetitanium trichloride catalyst, a titanium tetrachloride catalyst, or atitanium catalyst supported on silica can be used. Also, a Ziegler-Nattacatalyst and a single-site catalyst such as a metallocene can be used,or a transition metel catalyst can be used.

To obtain a high catalytic activity, it is desirable that a metallocenecatalyst, a titanium catalyst supported on silica, or a titaniumcatalyst supported on magnesium including a polymerization catalystsupported on magnesium are used.

The metallocene catalyst includes pentamethylcyclopentadienyizirconiumtrichloride, bis(pentamethylcyclopentadienyl)zirconium dichloride,indenyliirconium trichloride, bis(indenyl)zirconium dichloride,dimethylsillylene-bis(indenyl)zirconium dichloride,(dimethylsillylene)(dimethylsillylene)-bis(indenyl)zirconium dichloride,(dimethylsillylene)-bis(2-methyl-4-phenylindenyl)zirconium dichloride,(dimethylsillylene)-bisfbenzoindenyl)zirconium dichloride,ethylene-bis(indenyl)zirconium dichloride,(ethylene)(ethylene)-bis(indenyl)zirconium dichloride,(ethylene)(ethylene)-bis(3-methylindenyl)zirconium dichloride,(ethylene)(ethylene)-bis(4,7-dimethylindenyl)zirconium dichloride,(tert-butylimide)(tetramethyl-η5-cyclopentadienyl)-1,2-ethandiylzirconiumdichloride,(tert-butylimide)dimethyl(tetramethyl-η5-cyclopentadienyl)silanezirconiumdichloride,(methylamide)(tetramethyl-η5-cyclopentadienyl)-1,2-ethandiylzirconiumdichloride and the like.

It is preferable to use the following magnesium-supported polymerizationcatalyst as a Ziegler-Natta catalyst, since it's use is eco-friendlycontrary to the use of conventional phtalate type catalysts as aninternal electron donor.

That is, to the pretreatment reactants in the reaction that ahalogen-containing magnesium compound reacts with an organic compoundcontaining an activating hydrogen is added phthalic anhydride (PA) toform a homogeneous solution; a titanium chloride is added to thehomogeneous solution to recover a sphere-shaped granular carrier, to therecovered carrier is added the internal electron donor that has asilicon atom in dialkylpropane 1,3-diether based structure of theFormula 1 instead of a transitional metal compound and phthalate basedinternal electron donors, which are endocrine disruptors, to form themagnesium-supported polymerization catalyst. This catalyst can be usedas a catalyst in the polymerization of α-olefin having 3 or more ofcarbon atoms, and has eco-friendly properties and a high activity.

Wherein, R1 and R2 are aliphatic or aromatic hydrocarbon having from 1to 20 of carbon atom(s), R6 is aliphatic or aromatic hydrocarbon havingfrom 1 to 30 of carbon atom(s), R3, R4 and R5 are hydrogen or aliphaticor aromatic hydrocarbon having from 1 to 30 of carbon atom(s).

The internal electron donor has eco-friendly properties, contrary to thephthalate based internal electron donors that are endocrine disruptorsand that have been used frequently in the conventional catalytic system.Also, the compound used as the internal electron donor can be used as anexternal electron donors.

The chemical structure of the magnesium-supported polymerizationcatalyst has not been established yet but it comprises 1˜4% by weight oftitanium, 15˜30% by weight of magnesium, 60˜80% by weight of halogen andless than 1.0% by weight of silicone (Si).

Also, the main catalyst (i) can be used after prepolymerization withα-olefin such as ethylene or propylene.

As the co-catalyst (g), organometallic compounds of R_(N)MX_(3-N)(wherein, M is magnesium, boron, aluminium, zinc and the like, andrepresents the metals of group IA, IIA, IIB, IIIB or IVB of the periodictable, R is straight, branched or cycloalkyl group having from 1 to 20of carbon atom(s), X is halogen atom, n is an integer in the range of0<n≦3) are used.

Particular examples of the organometallic compounds can be selected fromthe group consisting of organic aluminium compound, that isdiethylaluminium chloride (DEAC), ethylaluminium dichloride (ADC),dinormalbutylaluminium chloride (DNBAC), diisobutylaluminium chloride(DIBAC), ethylaluminium sesquichloride (EASC), triethylaluminium (TEA),triisobutylaluminium (TIBA), trinormalhexylaluminium (TNHA),trinormaloctylaluminium (TNOA), trinormaldecylaluminium (TNDA),triethylzinc, triethylboran, triisobutylboran, methylaluminoxanes (MAO)and the like, or can be the mixture of two or more of the foregoingcompounds.

Preferably, diethylaluminium chloride (DEAC), triethylaluminium (TEA),triisobutylaluminium (TIBA) and methylaluminoxanes (MAO) can be used.

Further, the cocatalyst that is an external electron donor (h) can beintroduced to maximize the stereospecificity of the polybutylene.

For example, silane compounds, inorganic acids, hydrogen sulfides,ethers, diethers, esters, amines, organic acids, organic acid esters orthe mixture of two or more of the foregoing compounds can be used.

As the external electron donor (h), it is preferable to use alkyl-,aryl- or alkoxy-containing silane compound. As the particular examples,diphenyldimethoxysilane, phenyltrimethoxysilane, isobutylmethoxysilane,diisobutyldimethoxysilane, cyclohexylmethyldimethoxysilane, anddiisopropyldimethoxysilane can be used.

Also, as described above, the structurally particular internal electrondonor that has a silicon atom in dialkylpropane 1,3-diether basedstructure can be used as external electron donors (h).

In the present invention, it is important that the process is carriedout with increasing the pressure in the polymerization reactor usinginert gas (j), which does not take part in the reaction, to a higherpressure than gas-liquid equilibrium pressure of reactants at a givenreaction temperature, in order to increase the polymerization activityof the stereospecific polybutylene.

That is, it is possible to produce the polybutylene at a higher yield bypolymerization at a higher pressure than gas-liquid equilibrium pressureof reactants at a given reaction temperature by introducing inert gasthat does not take part in the reaction into batch reactor, CSTR oranother type of reactors in the presence of Ziegler-Natta catalyst etc.and organic aluminium compound.

The inert gas is the gas that dose not take part in the reaction whereinpolybutylene is produced by polymerizing 1-butene, and includesnitrogen, helium, neon, argon, crypton, xenon, radon or the mixture oftwo or more of the foregoing compounds. Preferably, the inert gas is anyone or more selected from the group consisting of nitrogen, helium andargon.

As the stabilizers and the additives (k), phenol based antioxidants,phosphorous or sulfur based antioxidants, thermal stabilizers,nucleating agents and the like that are used in the polymerization ofpolyolefin can be used, if necessary. Also, other stabilizers andadditives (k) can be further added.

The high stereospecific polybutylene polymer prepared by the presentinvention is a homopolymer of 1-butene or a copolymer containingα-olefin and up to 40% by weight of a comonomer, and has the followingproperties.

First, as shown in the following examples, titanium in catalyticresidues is not detected in ppm (weight) level.

Also, as shown in the following examples and appended figures, thestereospecificity (Isotactic Index, mmmm %) determined by ¹³C-NMR is 96or more.

The molecular weight distribution (Mw/Mn) of the polybutylene polymer is3˜6. The molecular weight distribution can be controlled and expanded toa molecular weight distribution (Mw/Mn) of 8 or more by the handling ofthe procedure as follows:

That is, when the polybutylene is prepared in CSTR, the molecular weightdistribution (Mw/Mn) can be controlled in the range of 3˜6 by using onlysingle reactor and one-stage polymerization. Meanwhile, when thepolybutylene is prepared in batch reactor, CSTR, other reactor, themolecular weight distribution (Mw/Mn) can be controlled to 8 or more byusing two or more same-type or different-type reactors that areconnected in series or in parallel for polymerization

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is ¹³C-NMR spectrum of polybutylene homopolymer that ispolymerized without an external electron donor (Lewis base)(See example10).

FIG. 1B is ¹³C-NMR spectrum of polybutylene homopolymer that ispolymerized with an addition of dimethoxy diisopropyl silane((i-Pr)₂Si(OCH₃)₂) as an external electron donor (Lewis base)(Seeexample 1).

FIG. 2 is ¹³C-NMR spectrum in the range of 26˜28 ppm of polybutylenehomopolymer that is polymerized without an external electron donor(Lewis base)(See example 10).

FIG. 3 is ¹³C-NMR spectrum in the range of 26˜28 ppm of polybutylenehomopolymer that is polymerized with an addition of an external electrondonor (Lewis base) to increase stereospecificity (See example 1).

BEST MODE FOR CARRYING OUT THE INVENTION

The present invention will be illustrated in more detail by thefollowing examples without limiting it.

EXAMPLE 1 Sample B

(a) Preparation of Catalyst

To a 1 L 4-neck round bottom flask equipped with a magnetic stirrer, acondenser and a temperature detector was added 50 ml of decane and 3.0 gof magnesium chloride under nitrogen gas stream, agitated for severalminutes, added 1 ml of 2-ethylhexanol, increased temperature to 130° C.over 20 min with agitation, and then reacted for 1 hr.

After reaction for 1 hr, 1.0 g of PA was added. The resulting mixturewas reacted for 1 hr at 130° C. with agitation under nitrogenatmosphere. The resulting homogeneous solution was cooled to ambienttemperature. Titanium tetrachloride was dropped at a low temperatureover 1 hr, and agitated to obtain slurry which contains solid product.

The solid product was filtered, separated and washed with heptane fourtimes. To the resulting solid product was added 50 ml of toluene, addedtitanium chloride with agitation, increased temperature to 100° C.,dropped 0.30 g of 2-isopropyl-2-trinethylsillylmethyl-1,3-dimethoxypropane, increased temperature to 110° C., and then reacted for 2 hrs.

On completion of the reaction, the solid product was filtered, separatedand washed with heptane four times. To the washed solid product wasadded heptane and titanium chloride, and reacted at 98° C. for 2 hrs.The resulting solid catalyst component was filtered, separated andwashed with heptane thoroughly until free titanium compound has not beendetected any more to obtain solid catalyst suspended in heptane.

The constituents of the obtained catalyst were analyzed with ICP. Theresults showed that there are 2˜3% by weight of titanium and 16˜19% byweight of magnesium.

(b) Polymerization for Stereospecific Polybutylene Polymer

A 2 L stainless steel autoclave to be used was vacuum-purged andnitrogen-purged repeatedly. To the autoclave was added 0.01 g of thesolid catalyst component in (a) above, 0.01 g ofdiisobutylmethoxysilane, 0.3 g of triethylaluminiumchloride (TEA), 1.2 Lof 1-butene and 200 ml of hydrogen under nitrogen gas stream, applied 3bar of pressure with nitrogen additionally, increased the temperature ofthe autoclave up to 80° C. and then carried out polymerization.

After one and half hrs, the autoclave was depressurized. The unreacted1-butene monomers were removed. The obtained polymer was dried at 90° C.for 12 hrs under the vacuum state.

The activity of the dried polybutylene polymer was 23,000 g-/g-cata.1.5h that was 15,300 g-/g-cata h; the molecular weight (Mw) was 430,000;the molecular weight distribution (Mw/Mn) was 3.22; the density was0.886; and the melting point was 116.9° C.; titanium was not detected inppm (weight) level.

The stereospecificity was assessed with NMR. The stereostructure of thepolybutylene can be judged from the shape of resonance peak in the rangeof 26˜28 ppm.

EXAMPLE 2

Polybutylene polymer was prepared by the same procedure as that ofexample 1 except that 6 bar of pressure was applied to the autoclavewith nitrogen additionally on polymerization.

The activity of the obtained polybutylene polymer was 32,400 g-/g-cata1.5 h that was 21,600 g-/g-cata h; the molecular weight distribution(Mw/Mn) was 3.69; the density was 0.884; the stereospecificity(Isotactic Index, mmmm %) was 99.7; and the melting point was 117.0° C.;titanium was not detected in ppm (weight) level.

EXAMPLE 3

Polybutylene polymer was prepared by the same procedure as that ofexample 2 except that 0.01 g of2-isopropyl-2-trimethylsillylmethyl-1,3-dimethoxy propane, which wasused as the internal electron donor in the above description, was usedas an external electron donor instead of diisobutylmethoxysilane onpolymerization

The activity of the obtained polybutylene polymer was 29,700 g-/g-cata1.5 h that was 19,800 g-/g-cata h; the molecular weight distribution(Mw/Mn) was 4.11; the density was 0.880; the stereospecificity(Isotactic Index, mmmm %) was 96.9; and the melting point was 115.6° C.;titanium was not detected in ppm (weight) level.

EXAMPLE 4

Polybutylene polymer was prepared by the same procedure as that ofexample 2 except that propylene was added as comonomer onpolymerization.

The activity of the obtained polybutylene polymer was 30,700 g-/g-cata1.5 h that was 20,500 g-/g-cata h; the molecular weight distribution(Mw/Mn) was 3.45; the density was 0.881; the methyl group on the mainchain is 14% (by weight); and the melting point is 116.5° C., 134.2° C.;titanium was not detected in ppm (weight) level.

EXAMPLE 5

A 50 L stainless steel autoclave to be used was vacuum-purged andnitrogen-purged repeatedly. To the autoclave was added 0.3 g of thesolid catalyst component produced by the same procedure as that ofexample 1, 0.3 g of diisobutylmethoxysilane, 0.12 g oftriethylaluminiumchloride (TEA), 25 L of 1-butene and 10 bar of hydrogenunder nitrogen gas stream, applied 4 bar of pressure with nitrogenadditionally, increased the temperature of the autoclave up to 80° C.and then carried out polymerization.

After one and half hrs, the polymer in the autoclave was transferred toa subsequent stirred tank added BHT as an antioxidant, and depressurizedto remove unreacted 1-butene monomers. The obtained polymer was dried at90° C. for 12 hrs under the vacuum state.

The activity of the dried polybutylene polymer was 28,300 g-/g-cata 1.5h that was 18,900 g-/g-cata h; the molecular weight distribution (Mw/Mn)was 4.05; and MFR was 0.382; titanium was not detected in ppm (weight)level.

EXAMPLE 6

Used a facility comprising 2 parallel connected polymerization reactors(50 L, autoclaves), a subsequent stirred tank (100 L) and an apparatusfor pressure-reducing and recovery, the two 50 L stainless steelautoclaves to be used were vacuum-purged and nitrogen-purged repeatedly.To the autoclaves were added 0.3 g of the solid catalyst componentproduced by the same procedure as that of example 1, 0.3 g ofdiisobutylmethoxysilane, 0.12 g of triethylaluminiumchloride (TEA), 25 Lof 1-butene and 10 bar of hydrogen under nitrogen gas streamrespectively, applied 4 bar of pressure with nitrogen additionally,increased the temperature of the one autoclave up to 70° C. and thetemperature of the other autoclave up to 80° C., and then carried outpolymerization.

After one and half hrs, the polymer in the respective autoclave wastransferred to the subsequent stirred tank simultaneously, mixed, addedBHT as an antioxidant, and depressurized to remove unreacted 1-butenemonomers. The obtained polymer was dried at 90° C. for 12 hrs under thevacuum state.

The activity of the dried polybutylene polymer was 27,800 g-/g-cata 1.5h that was 18,500 g-/g-cata R; the molecular weight distribution (Mw/Mn)was 7.4; and MFR was 0.45; titanium was not detected in ppm (weight)level.

EXAMPLE 7

A 50 L stainless steel autoclave equipped with automatic on-off controlvalve to be used was vacuum-purged and nitrogen-purged repeatedly. Tothe autoclave was added 0.3 g of the solid catalyst component producedby the same procedure as that of example 1, 0.3 g ofdiisobutylmethoxysilane, 0.12 g of triethylaluminiumchloride (TEA), 25 Lof 1-butene and 10 bar of hydrogen under nitrogen atmosphere, applied 4bar of pressure with nitrogen additionally, increased the temperature ofthe autoclave up to 80° C. and then carried out polymerization. Afterone and half hr, the polymerization was carried out using CSTR.

The residence time was set as one and half hr. The natural loss ofpressure caused by the diffluence of nitrogen dissolved in liquid out ofthe reactor was compensated by supplementing nitrogen. The amount of thecharge of the solid catalyst component produced by the same procedure asthat of example 1 and triethylaluminiumchloride was controlled accordingto the difference of reaction temperature with maintaining thetemperature in the reactor constantly.

After one and half hrs from the initiation of the polymerization, anamount of the polymer in the autoclave was transferred to a subsequentstirred tank. When the predetermined amount of polymer was transferred,added BHT as an antioxidant, and depressurized to remove unreacted1-butene monomers. The obtained polymer was dried at 90° C. for 12 hrsunder the vacuum state.

The average activity of the dried polybutylene polymer was 19,200g-/g-cata h; the molecular weight distribution (Mw/Mn) was 4.88; and Mwas 0.37; titanium was not detected in ppm (weight) level.

EXAMPLE 8

Used a facility comprising two 50 L stainless steel autoclaves equippedwith automatic on-off control valve respectively, a subsequent stirredtank (100 L) and an apparatus for pressure-reducing and recovery, thetwo 50 L stainless autoclaves to be used were vacuum-purged andnitrogen-purged repeatedly. To the autoclaves was added 0.3 g of thesolid catalyst component produced by the same procedure as that ofexample 1, 0.3 g of diisobutylmethoxysilane, 0.12 g oftriethylaluminiumchloride (TEA), 25 L of 1-butene and 10 bar of hydrogenunder nitrogen atmosphere respectively, applied 4 bar of pressure withnitrogen additionally, increased the temperature of the one autoclave upto 70° C. and the temperature of the other autoclave up to 80° C., andthen carried out polymerization. After one and half hr, thepolymerization was carried out using CSTR.

The residence time was set as one and half hr. The natural loss ofpressure caused by the diffluence of nitrogen dissolved in liquid out ofthe reactor was compensated by supplementing nitrogen. The amount of thecharge of main catalyst and triethylaluminiumchloride was controlledaccording to the difference of reaction temperature with maintaining thetemperature in the reactor constant.

After one and half hrs from the initiation of the polymerization, anamount of the polymer in the respective autoclaves was transferred tothe subsequent stirred tank and mixed. When the predetermined amount ofpolymer was transferred, added BHT as an antioxidant, and depressurizedto remove unreacted 1-butene monomers. The obtained polymer was dried at90° C. for 12 hrs under the vacuum state.

The average activity of the dried polybutylene polymer was 17,900g-/g-cata h; the molecular weight distribution (Mw/Mn) was 4.88; and MFRwas 0.45; titanium was not detected in ppm (weight) level.

EXAMPLE 9

Polybutylene polymer was prepared by the same procedure as that ofexample 1 except that an additional pressure was not applied to theautoclave with nitrogen.

The activity of the obtained polybutylene polymer was 14,700 g-/g-cata1.5 h that was 9,800 g-/g-cata h; the molecular weight distribution(Mw/Mn) was 3.93; the density was 0.884; the stereospecificity(Isotactic Index, mmmm %) was 96.7; and the melting point was 117.4° C.;titanium was not detected in ppm (weight) level, but the polymer has alight color of bright redyellow.

EXAMPLE 10

Polybutylene polymer was prepared by the same procedure as that ofexample 2 except that cocatalyst (h) diisobutylmethoxysilane, anexternal electron donor, was not introduced to the autoclave onpolymerization.

The activity of the obtained polybutylene polymer was 35,200 g-/g-cata1.5 h that was 23,500 g-/g-cata h; the molecular weight distribution(Mw/Mn) was 4.11; the stereospecificity (Isotactic Index, mmmm %) was61.0; and the melting point was 108.5° C.; titanium was not detected inppm (weight) level.

EXAMPLE 11

A catalyst was prepared by the same procedure as that of example 1except that 0.43 g of dinormalbutylphthalate (DNBP) instead of2-isopropyl-2-trinethylsillylmethyl-1,3-dimethoxy propane was introducedas an internal electron donor. Polybutylene was prepared by the sameprocedure as that of example 2.

The activity of the obtained polybutylene-propylene copolymer was 27,600g-/g-cata 1.5 h that was 18,400 g-/g-cata h; the molecular weightdistribution (Mw/Mn) was 3.55; the density was 0.886; thestereospecificity (Isotactic Index, mmmm %) was 98.2; and the meltingpoint was 116.7° C.; titanium was not detected in ppm (weight) level.

FIG. 1A is ¹³C-NMR spectrum of polybutylene homopolymer that ispolymerized without an external electron donor (Lewis base) according tothe present invention (See example 10). FIG. 1B is ¹³C-NMR spectrum ofpolybutylene homopolymer that is polymerized with an addition ofdimethoxy diisopropyl silane ((i-Pr)₂Si(OCH₃)₂) as an external electrondonor (Lewis base)(See example 1).

The stereostructure of polybutylene can be determined from resonancepeak of methylene carbon that is in ethyl branch of 1-butene unit(indicated as ‘{circle around (2)}’ in FIG. 1). As the stereospecificity(Isotacticity) is higher, the resonance peak similar to singlet peakcomes to appear in the range of 26˜28 ppm.

As shown in FIG. 1A, very, complicate resonance peak (multiplet peak)appeared in the range of 26˜28 ppm because of the reduction ofstereospecificity of polybutylene. Also, as shown in FIG. 1B,approximately perfect single resonance peak appeared in the range of26˜28 ppm because of the enhancement of stereospecificity caused by anexternal electron donor (Lewis base).

FIG. 2 is ¹³C-NMR spectrum in the range of 26˜28 ppm of polybutylenehomopolymer that is polymerized without external electron donor (Lewisbase) according to the present invention (See example 10). This is thespectrum of high stereospecific samples that are dissolved in ether, andis the spectrum of low stereospecific samples that are not dissolved inether by using ether extraction fractionation to separate obtainedpolymer into stereospecific samples and non-stereospecific samples.Although large amount of samples were used, low stereospecific samplesthat are not dissolved in ether were obtained little.

As shown in FIG. 2, using the extraction fractionation, even astereospecific polymer that is not dissolved in ether containsnon-stereospecific units in the main chain.

FIG. 3 is ¹³C-NMR spectrum of polybutylene homopolymer that ispolymerized with an addition of an external electron donor (Lewis base)to increase stereospecificity (See example 1).

Although large amount of samples were used, low stereospecific samplesthat are dissolved in ether were obtained too little to determine¹³C-NMR spectrum. As shown in FIG. 3, the obtained polymer shows onlysingle resonance peak in the enlarged spectrum in the range of 26˜28 ppmand the stereospecificity (Isotactic Index, mmmm %) is high to 0.987.

INDUSTRIAL APPLICABILITY

As described above, the process for the preparation of the polybutyleneof the present invention has much higher activity than that of any otherknown processes for the preparation of polybutylene and, therefore,exhibits a high activity similar to that of a highly active process forthe preparation of polyethylene or polypropylene. Thus, the productivityof the polybutylene according to the present invention is improvedgreatly.

Also, the effect that the process of the present invention has can beachieved by using known CSTR, tubular reactor (PFR) and other reactorsas well as batch reactor.

Further, the polybutylene prepared by the process of the presentinvention has such a high purity of the catalyst residues that titaniumis not detected in ppm (weight) level contrary to the conventionalstereospecific polybutylene.

1. A process for the preparation of a high stereospecific polybutylenepolymer, comprising the step (S1) of polymerizing a reactive monomer,1-butene, which is used or is not used as a solvent, in the presence ofcatalyst, and in the presence of an inert gas by intentionallyintroducing the inert gas to a reactor with hydrogen in order that theinert gas is present in the reactor during the polymerization even afterreactor purging, wherein the step S1 is carried out with increasingpressure in a polymerization reactor using the inert gas to a higherpressure than gas-liquid equilibrium pressure of reactants at a givenreaction temperature.
 2. The process according to claim 1, wherein thestep S1 is carried out with using the inert gas which is one or moreselected from the group consisting of nitrogen, helium and argon.
 3. Theprocess according to claim 2, wherein the reaction temperature in thestep S1 is 10° C. to 110° C.